This invention relates generally to combustor liners for gas turbine engines and more particularly to liners which are assembled from a plurality of annular bands.
A gas turbine engine includes a compressor that provides pressurized air to a combustor wherein the air is mixed with fuel and ignited for generating hot combustion gases. These gases flow downstream to one or more turbines that extract energy therefrom to power the compressor and provide useful work such as powering an aircraft in flight. Combustor used in aircraft engines typically include inner and outer combustor liners to protect the combustor case and surrounding engine components from the intense heat generated by the combustion process.
One particular type of combustor liner is comprised of a plurality of annular sheet metal bands that are joined together at overlapping circumferential joints to form an assembled liner. Prior art inner and outer liners of this type are presently constructed by brazing the sheet metal bands together at the overlapping joints. The process involves tack welding the bands in place, followed by manually applying a braze filler at each braze joint, followed by a furnace cycle braze operation. The braze joints are then inspected, for example by x-raying the joints. A large proportion of liners joined in this manner, in some instances over 90%, exhibit defects such as voids in the braze joints, which require a second braze operation involving the application of more slurry in the areas which have braze voids and a subsequent second furnace cycle and additional x-ray inspection. Brazing of the liners is costly and increases the manufacturing cycle time needed to produce the liners.
Accordingly, there is a need for combustor liners having a lower cost and simplified manufacturing process.
The above-mentioned need is met by the present invention, which provides a combustor liner having first and second annular bands which have an overlapping circumferential joint area. A weld is disposed in the joint area and encompasses substantially all of the axial length of the joint area. The invention also provides a method for producing such a combustor liner.
The present invention and its advantages over the prior art will become apparent upon reading the following detailed description and the appended claims with reference to the accompanying drawings.